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Depression: 'Orphan' brain receptor may be to blame

Monday 05/March/2018 - 02:54 PM

New research uncovers a brain receptor that could explain why some people experience major depressive disorder after a stressful event، while others do not.Recently، an increasing amount of studies have been focusing on the neurological causes of depression، which is a psychiatric condition affecting more than 16 million adults in the United States.

Only a few months ago، one such study pointed out that depression originates in brain areas associated with memory and reward.

And، just a few days ago، another study laid out an electrical brain map of depression that could predict who develops the condition.

Now، researchers from The Scripps Research Institute (TSRI) in Jupiter، FL، may have uncovered a new drug target for the treatment of depression.

Scienitsts led by Kirill Martemyanov، Ph.D. — co-chair of the TSRI Department of Neuroscience — focused on a brain receptor called GPR158 after they noticed that levels of the GPR158 protein were very high in people with depression.Medics Today said.

So، Martemyanov and colleagues examined the behavior of this brain receptor in mice that had been subjected to chronic stress. Their findings were published in the journal eLife.

Studying 'orphan brain receptors' in miceThe researchers examined both rodents that had the receptor and those that did not. Exposing the mice that did have GPR158 to chronic stress increased the levels of the protein in the rodents' prefrontal cortices.

Martemyanov and colleagues also noticed that excessive levels of GPR158 led to behavioral signs of depression in mice such as anhedonia — or the sudden inability to enjoy activities that used to be pleasurable — and anxiety-like physiological reactions.

By comparison، the researchers report that genetically removing GPR158 "led to a prominent antidepressant-like phenotype and stress resiliency،" in the mice.

Martemyanov explains that GPR158 brain receptors are called "orphan receptors" because it is not yet known what chemical the protein binds to.

These are "proteins that look like they will bind and respond to a hormone or a brain chemical، based on the similarity of their sequences to other proteins." However، their binding partner(s) remain mysterious.